The present invention is related to an apparatus and process for flushing intravenous tubing (IV) after a prescribed medication has been administered through the IV. More particularly, the present invention is directed to using a flush chamber connected to the intravenous piggyback tubing system to allow the tubing to be flushed without additional needle sticks into the venous access device.
2. Description of Related Art Including Information Disclosed Under 37 C.F.R. Sections 1.97-1.99
In medical practice, it is often necessary to administer liquids to a patient intravenously. Such infusions are customarily carried out by employing intravenous kits that incorporate a supply bottle or other container of liquid that is suspended above a patient. A drop counting or drip chamber meters the dosage and gravity causes the liquid to flow through a drip tube to a venous access device (VAD), that is, a saline lock or other solution lock, which is implanted in the patient, typically in a peripheral vein in the arm.
Liquids so administered include, for example, fluids such as normal saline, blood, plasma, dextrose, glucose solutions and the like. Increasingly, however, drugs or medications, especially antibiotics are often administered through an IV device in relatively small quantities, for example, 50-150 cubic centimeters (cm) or milliliters (ml). Often such medicines are administered through intravenous tubing or IV package, but without administering any additional fluid from another bag or vessel. This procedure is followed after a patient has been fully rehydrated, if necessary, and does not need infusions of large volumes of fluid.
The infusion rate is controlled in the drip chamber by a flow controller, such as a pinch clip. When infusions are carried out, the drip tube and needle are initially purged of air, the needle is inserted into the patient, or more commonly, into the venous access device, which is separately inserted into a vein, usually in the arm. The flow controller compresses the drip tube to restrict the initial flow of liquid. The number of drops, and hence the dosage, of a liquid falling through the drip chamber are determined by trial and error adjustment of the flow controller.
Antibiotics in particular are administered intravenously because they work better when infused directly into the bloodstream than when taken orally. When administered orally, much of the dosage is destroyed in the stomach or absorbed directly by the stomach, where it is less effective than it is in the bloodstream.
Therefore, patients in need of antibiotics in a hospital are frequently given the medication intravenously for about 5-7 days, and then switched to oral medication. The antibiotics or other medications are normally administered three times each day. A period of about 30-60 minutes is required for the medications to be infused into the bloodstream by this method.
When the IV bag is empty, a health care worker removes the IV tubing from the venous access device by withdrawing the IV needle from the rubber diaphragm of the venous access device. Then the health care worker inserts a syringe needle into the diaphragm of the venous access device and flushes the venous access device with a solution to prevent clogging of the venous access device. This solution may be an anticoagulant, which is sometimes considered necessary to prevent clotting and clogging, or normal saline solution, which is frequently now used efficaciously for the same purpose.
Thus, each time a dose of medication is administered in this fashion, two needle sticks of the venous access device are required, one to insert the IV and a second to flush the venous access device after the medicine has been administered.
If a medicine in intravenously administered three times each day for five days to one patient, then 30 needle sticks of the venous access device are required during the course of IV treatment. Each of these needle sticks presents the possibility of introducing organic or infectious agents into the patient's bloodstream and the possibility of an accidental needle stick into the health care worker.
Another problem with the standard IV apparatus is that some of the medicine prescribed by the physician and typically administered by a nurse remains in the IV tubing itself, never reaching the patient. This lost medication can amount to a substantial portion of the total dosage, but physicians typically do not take this lost dosage into account when prescribing a medicine. Further aggravating this problem is the fact that IV sets provide drip tubes of widely differing inside diameters and the health care worker usually simply grasp whatever IV set is handy, so there is not any reliable way to predict exactly what proportion of the prescribed medication will remain in the IV tubing. Typically, however, it can be expected that about 3-8 cc of the medicine will remain in the tubing, which typically results in 5%-15% of the total dosage not being administered to the patient. The shortfall in medication that results sometimes depends on the patient's body weight, which is usually the basis for the prescribed dosage, and the inside diameter of the IV tubing.
As may be imagined, IV sets and the catheters they so closely resemble are useful in many health care situations and much inventive effort has been devoted to improving and refining them, as is demonstrated by the related art known to the applicant, which is discussed below.
U.S. Pat. No. 5,002,528, issued to Palestrant on Mar. 26, 1991 (Palestrant U.S. Pat. No. '528) discloses a "Percutaneous Irrigation and Drainage System" comprising an irrigation fluid reservoir located above the patient. The reservoir is connected to other elements of the invention via a three-ported connector which is also connected to a drainage bag. A body cavity of the patient is drained into the drainage bag through a small catheter. In such situations it is often necessary to irrigate the catheter several times each day to maintain the flow. This invention reduces the number of times that connections must be made and broken to accomplish the necessary irrigation. The invention does not address the problem administering medications via IV sets.
U.S. Pat. No. 4,902,282, issued to Bellotti et al. on Feb. 20, 1990 (Bellotti et al. U.S. Pat. No. '282) discloses a "Tuned Cycler Set" comprising a plurality of interconnected tubes for administering peritoneal dialysis solution in an automated peritoneal dialysis procedure. Controlling means are used to cause the flow path resistance through each flow path to be substantially equal.
U.S. Pat. No. 4,892,524 issued to Smith on Jan. 9, 1990 (Smith U.S. Pat. No. '524) discloses an "Intravenous Administration System" comprising an apparatus designed to assure a steady and unchanging overall flow rate of medicine through the system without the flow rate being affected by changes in the overall pressure of the system, such as those pressure changes caused by changes in the patient's blood pressure or physical movement. The apparatus includes a supply bottle connected to a passive meter and a regulator. The device also prevents air from flowing through it into the patient.
Aall-Flood et al. U.S. Pat. No. '787 discloses an "Apparatus for Preventing Back-Flow of fluid in a Blood Filtering System" comprising a check valve for preventing fluid back-flow between a pump and a pressure equalizer. The apparatus is employed in a blood filtering system.
Archibald U.S. Pat. No. '506 discloses a "Multiple Solution IV System with Setup Error Protection" comprising a plurality of IV sources of different solutions and a sequence valve that controls the volume of each solution that is administered to the patient and the sequence in which the solutions are administered. A pump controls and measures the accumulated volume of solution taken from each source. The care giver enters the desired volume and sequence for each solution and the invention automatically follows those instructions.
Riddell U.S. Pat. No. '334 discloses an "Intravenous Drug Infusion Apparatus" comprising a small drug mixing vessel holding a concentrated solution of medication that is connected to a VAD in the patient. A larger vessel containing a low concentration of the same medicine is physically higher than the small vessel and is connected to it by a tube that penetrates the small vessel. As solution is drained from the small vessel into the patient, it is replaced by fluid from the larger vessel, continually diluting the concentration of the medicine being administered to the patient. The invention is designed to administer a concentrated dose initially when it can be readily absorbed and utilized by the patient and to automatically decrease the dosage rate as time passes until the patient is receiving a maintenance dosage.
A Russian reference number 171962 appears to include a fluid vessel connected to a depending tube, with a portion of the tube being secured to some type of measurement device similar to a ruler or a barometer. The reference further includes a separate, lower vessel covered by a stopper which may be connected to the higher vessel, which includes an instrument along a tube from it, perhaps a thermometer. The lower vessel has a depending tube connected to it, which is in turn connected to the tubing. The reference discloses the use of two fluid reservoirs connected to a single tube with one vessel higher than the other.
None of these prior art efforts in the related field address the problems encountered in using intravenous sets for administering short antibiotics, which are summarized below.
Each time that a health care worker must attend to a patient, for example, to administer a new medication, alter a dosage, monitor a dosage, and so forth the cost of the labor involved in treating the patient increases. Clearly, having to return to a patient and remove the IV set and separately flush the venous access device increases labor costs. Further, a new syringe is used and then discarded each time the venous access device is flushed, increasing the cost of medical supplies to the patient. An apparatus and method that reduces the number of needle sticks required during the course of treatment will therefore reduce the costs of treating a particular patient.
Each time that the diaphragm of the venous access device is punctured by a needle, the risk of infection to the patient increases because it increases the possibility of introducing foreign matter into the patient's bloodstream. Conventionally, this diaphragm is punctured twice each time a dose of medication is administered, once to actually administer the medication and once to flush the venous access device.
The potential spread of Acquired Immune Deficiency Disease (AIDS) among health care workers has become a major concern. A primary source of this potential spread of AIDS is thought to be blood to blood contact caused by accidental needle sticks by health care workers to themselves. Use of intravenous systems for administering fluids and medications to patients is a major source of needle sticks to health care workers.
Therefore, a need exists for an apparatus and process that reduces the number of needle sticks required in the intravenous administration of medications, thereby reducing the possibility for accidental needle sticks into health care workers.